This invention relates to separable fasteners, in general, and, in specific, to separable fasteners that will be attached to a molded article, such as a seat cushion.
One portion of such a separable fastener is typically incorporated into the molded object, such as a polyurethane seating foam, during a molding process, for subsequent attachment to another object carrying the mating portion of the separable fastener. The fastener of this invention greatly simplifies the method of molding the part to which it is attached. Although particular reference is made herein to elastomeric polyurethane foam or hard plastic parts, it is to be understood that a fastener product according to this invention can be used in parts made from a wide variety of materials, e.g. thermoplastic materials, thermoset materials, elastomers, or any other moldable composition.
Hook and loop separable fasteners, such as those sold by the assignee of this invention under the trademarks xe2x80x9cVELCROxe2x80x9d and xe2x80x9cULTRAMATE,xe2x80x9d are well known and used to join two members detachably to each other. This type of fastener has two components. Each has a flexible substrate or base having one component of the fastening system on the surface thereof. One surface typically carries resilient hooks while the other carries loops. When the two surfaces are pressed together they interlock to form a releasable engagement.
The hooks can be any of a variety of shapes, including cane-shaped, palm tree-shaped and mushroom-shaped, all of which are well known within the art. As used within this application, the terms xe2x80x9chook,xe2x80x9d xe2x80x9chook-typexe2x80x9d and xe2x80x9chook-likexe2x80x9d shall be construed to mean any such configuration of loop-engaging element.
Separable fasteners are used in the manufacture of automobile seats in the attachment of an upholstered seat cover, (xe2x80x9ctrim coverxe2x80x9d), to a polyurethane foam bun. One portion of the separable fastener is incorporated into the surface of the polyurethane seat bun during the foam molding process. The mating portion of the separable fastener is attached to the seat cover to provide releasable attachment to the foam seat bun. The separable fastener assembly used in the foam mold for incorporation in the bun surface typically is the hooked portion of the separable fastener system. This hook portion has a base carrying resilient hooks on one surface. The surface of the base obverse of the hook-carrying surface may act as an anchoring surface by a variety of configurations well known in the art.
In some assemblies a magnetically attractive material is attached to the base to facilitate placement of the assembly in a trough of the mold cavity wall, which is equipped with magnets. It is also possible to incorporate magnetically attractive material into the body of the fastener itself, such as in a plastic material that is used to make the fastener. This is described in detail in U.S. Pat. No. 5,725,928, issued on Mar. 10, 1998, entitled TOUCH FASTENER WITH MAGNETIC ATTRACTANT, assigned to Velcro Industries B.V., inventors, Brian J. Routhier, Randall B. Kenney and Martin I. Jacobs, the disclosure of which is hereby incorporated herein by reference.
Such fastening devices are applied to one surface of a clamshell mold; a chemical mixture, for instance of a diisocyanate and a polyol, is injected into a mold; the upper surface of the mold is closed and clamped shut while the chemicals react and blow to form a flexible foam, well known in the art.
A protective layer, often in the form of a thin plastic film, may be placed over the resilient hooks (before they are placed in the mold) to prevent incursion of foam into the hooks during the molding process. Significant foam contamination of the hooks would diminish their ability to engage with the mating portion of the fastener.
Prior-art assemblies, including those disclosed in U.S. Pat. No. 4,673,542, inventor Wigner et al., U.S. Pat. No. 4,563,380, inventor Black et al., and U.S. Pat. No. 4,693,921, inventor Billarant et al., employ a thin, enveloping film to prevent the incursion of foam into the fastener elements of the separable fastener during molding. French Patent 2,423,666 discloses a system for sealing the edges of the tape in the mold trough by jamming the edges of the fastener into the trough.
Two patents, which are assigned to the assignee hereof, disclose another arrangement for protecting the fastening elements from degradation and fouling by the foaming material. U.S. Pat. No. 5,286,431, issued on Feb. 15, 1994, to Banfield and Rocha, entitled MOLDED PRODUCT HAVING INSERT MOLD-IN FASTENER, discloses a fastener of the hook and loop type having a base member and a plurality of engaging elements upstanding from one surface thereof. A flexible (e.g. elastomeric or rubber) encasement (which may be either thermoplastic or thermoset) that intimately surrounds the individual engaging elements, substantially filling all of the space around each one, protects the elements when they are exposed to the harsh environment of a molding process. The fastener is placed in a mold and molded into, as an integral part thereof, a molded part. The encasement is removable from the engaging elements after the molding process, to expose the engaging elements, without permanently deforming or substantially destroying the fastening performance thereof. U.S. Pat. No. 5,540,970, issued on Jul. 30, 1996 to Banfield et al., entitled DIE CUT MOLD-IN, further discloses providing the flexible cover so that the tips of the hooks are slightly exposed. Other modifications of the invention are shown in the ""970 patent as well. The disclosures of both of these patents are incorporated fully herein by reference.
All of the arrangements discussed above that entail covering the fastening elements that are to be used to attach the molded product to a trim cover or companion piece, require that the molding operation include a step to remove the protective cover, be it a film-like cover or a space filling, encasing cover. This entails an inconvenience for the molding operator. Further, once removed, the cover is in the possession of the molding operator, who must dispose of it. But, the molding operator is not the one who could reuse the cover, even if it were to be recyclable. (It is the fastener manufacturer who is in the best position to reuse the cover.) Thus, from the perspective of the molding operator, it is very beneficial to be able to use a fastening component that does not require a removable cover. Consequently, those whose business it is to make the fastening component to be incorporated into the molded article are interested in providing to the molding operator a component that does not have a cover that needs to be removed after molding.
It is also typically desirable to avoid any apparatus that can not be used with a conventional mold, having a simple flat bottom trench for placement of the fastening element. Otherwise, the molding operator must alter its normal equipment and way of doing business.
Thus, there are, so called xe2x80x9ccoverlessxe2x80x9d products, which protect the fasteners without a separate cover. One such product is described in U.S. Pat. No. 5,606,781, issued on Mar. 4, 1997, entitled, SEPARABLE FASTENER HAVING A BALD PERIMETER RIB BOUNDED BY FASTENING ELEMENTS, also assigned to the assignee hereof, inventors, George Provost, Brian J. Routhier and Martin I. Jacobs. This product has a fastener with a central fastening area of fastening elements, surrounded by a region that has no hooks (into which a mating portion of the mold may fit) which is in turn surrounded by a ring of fastening elements that are xe2x80x9csacrificial,xe2x80x9d in the sense that they may become fouled with molding material, but they will prevent the incursion of the molding material into the interior, fastening area. The disclosure of this ""781 patent is hereby incorporated herein by reference.
U.S. Pat. No. 5,786,061, issued on Jul. 28, 1998, to the present assignee, entitled SEPARABLE FASTENER HAVING A PERIMETER COVER GASKET, inventor Donald Banfield, discloses a fastener having a flexible, space filling cover as described above in connection with either U.S. Pat. Nos. 5,286,431 or 5,540,970, but where the gasket covers only the perimeter hooks, with an internal coverless region. This gasket cover can remain on the fastening element after the molding operation has completed, thereby eliminating the need to dispose of a removed cover.
Other patents that disclose a gasket type approach to this problem are those assigned to Velcro Industries B.V., in the name of Hatch, including, U.S. Pat. Nos. 4,726,975 and 4,814,036, which describe a flexible sealing lip that is applied along the elongated marginal edges of a fastening element. Also of interest is U.S. Pat. No. 4,842,916, assigned to Kuraray Company, Ltd., inventor Ogawa, which describe gaskets of fiber, and, in some cases, foam.
Another challenge to using fasteners of the type described above in connection with molded products, foam or otherwise, is that it is often desirable to attach the fastener to a contoured surface, perhaps one that curves through three dimensions. All of the fasteners described above, in their basic configuration, are made as continuous elongated rectangular sheets, which are typically used as is, or stripped into narrower strips, all of which remain basically rectilinear.
Such narrow strips can be bent, relatively easily, through two dimensions, out of the plane of the strip. However, bending in the plane of the strip would result in creasing or puckering, as would bending around two or more axis in three dimensions. Bending is further complicated by some of the covering schemes disclosed above, as bending may cause the cover to buckle or separate from the substrate, and thus to fail for its intended purpose.
It is possible with some, but not all of the designs discussed above, to make large planar sheets and cut any shape desired therefrom. However, this procedure typically results in a relatively high amount of waste material. Further, one is still presented with a basically flat piece of material that must be bent to fit a contoured shape. Another possible solution is to use numerous separate relatively small fasteners, each of which must be separately placed in and fixed to the mold. This is undesireable because it requires significant operator handwork or specialized machinery.
Thus, the several objectives of the invention include to provide a fastener that can be secured to the surface of a molded object having virtually any contour, without requiring special cutting of shapes, or placing separate fasteners, and without significant waste of material, and time. Another objective of the present invention is to provide a fastener that has an integral barrier against foam intrusion, which economically, simply and securely protects the fastening elements from being fouled by foaming material. It is a further objective of the invention to provide both the contour and foam barrier features in the same product, without the solution to one problem limiting the effectiveness of the solution to the other.
In general, according to the present invention, a segmented fastener is used to accommodate molding contours. Each segment may be surrounded by a gasket barrier, or covered by another sort of cover, or left unprotected.
A preferred embodiment of the invention is a separable fastener component for use with a complementary separable fastener component. The separable fastener component comprises a plurality of fastening segments. Each fastening segment comprises a base member, having a nominal fastening face and a non-fastening face; and carried on the fastening face of the base member, a plurality of fastening elements, either hook-type or loop-type. Located between and joining each adjacent pair of fastening segments is a flexible neck that is narrower than the fastening segment. The flexible neck region is typically flexible around two or three orthogonal axes.
For each of the fastening segments, there may be a barrier for use during an operation to incorporate the fastener into a molded body, using a mold having a wall, which barrier would prevent any liquid foaming material from contacting a major portion of any of the fastening elements if the fastener is placed in the mold with the fastening elements pressed against the wall of the mold. The cover may be an enveloping type, or a space filling type, that substantially fills any spaces among the fastening elements. Or, it may, when used with hook type fastening elements, leave just the tips of the hooks exposed. The space filling cover may comprise an elastomeric, a thermoplastic, or a thermoset. It is typically flexible.
Rather than a cover, there may be, for each segmented fastening region, a gasket that extends fully around the perimeter of the segmented region. The gasket may be a perimeter lip that has been integrally formed with the fastening elements, or that has been applied to the base member separately from the fastening elements. If the fastening elements comprise hook-type elements having free tips, it is beneficial that the gasket comprise a flexible lip that extends away from the base slightly further than the tips. The gasket may comprise a perimeter space filling gasket that covers fastening elements in a perimeter region of the fastening segment.
Alternatively, according to another preferred embodiment, the fastening segments comprise an internal region that carries the fastening elements and a perimeter region that carries no fastening elements, the gasket comprising a perimeter space filling gasket that covers the perimeter region that carries no fastening elements.
The base may comprise magnetically attractable material.
According to still another preferred embodiment, the invention is a method for forming a separable fastener component for use with a complementary separable fastener component. The method comprises the steps of forming a plurality of fastening segments. Each fastening segment comprises a base member, having a nominal fastening face and a non-fastening face; and carried on the fastening face of the base member, a plurality of fastening elements selected from the group consisting of hook-type and loop-type elements. The method further comprises the step of joining each adjacent pair of fastening segments with a flexible neck that is significantly narrower than the fastening segment.
The step of forming a plurality of fastening segments comprise the step of providing, on a mold body, a plurality of spaced apart mold cavities shaped to form the fastening segments and between and joining each of the fastening segment mold cavities, a mold cavity shaped to form the flexible neck. The method also includes providing molding material to the mold cavities under sufficient pressure to force the molding material into the mold cavities; and removing the molding material from the cavities after the material has been formed into the fastening segments connected by the necks, to form the fastener component.
The step of providing molding material may comprise providing molding material to the mold cavities directly through an extrusion nozzle that is closely spaced from the mold cavities.
The mold body may comprise a mold wheel carrying the mold cavities on a peripheral edge. The step of providing molding material may comprise: providing a second wheel with a peripheral edge closely spaced from the mold wheel so as to form a nip therebetween; and providing molding material to the nip such that molding material is forced into the mold cavities under pressure generated at the nip between the molding wheel and the second wheel.
According to another preferred embodiment of the invention, the mold body may comprise a plurality of mold plates having similarly curved arcuate edges that are arranged parallel to each other, the mold cavities being formed in the arcuate edges. The mold plates may be circular, or segments of a circle, where the arcuate edges of the segments comprise a portion of a circle, certain of the mold plates being supported so that they are movable in a radial direction relative to the arcuate edge, thereby facilitating removal of a molded fastener component from the mold cavities, the step of removing molding material from the cavities comprising the step of moving radially inward the movable plates so as to release the molded material.
According to still another embodiment of the invention, the step of providing molding material comprises providing molding material to the mold cavities through an injection mold having at least two parts.
Still another embodiment of the invention contemplates A molded polymeric body, the body comprising an internal body volume; at least one surface; and a separable fastener component, according to any of the embodiments discussed above, adhered to the surface. The fastener component may be arranged such that segments of the fastener component are angled relative to each other, within a plane defined by the base members of the fastening segments.
Yet another embodiment of the invention is a method for forming a molded polymeric body as described above, carrying a segmented, separable fastener component as described above. The method comprises the steps of providing a mold, having at least one surface that has a trench therein, where the trench follows a path that has at least two portions that are angled relative to each other in a plane; and, locating in the trench a separable fastener component as described above. The method further includes providing liquid molding material into the mold such that the molding material substantially covers at least the surface of the mold in which the trench resides, and such that molding material contacts a significant portion of the base member of the fastening component, while simultaneously preventing the liquid molding material from contacting the fastening elements. The molding material is allowed to solidify to form the molded polymeric body, whereby the fastening component is secured to the molded body.
The invention also contemplates, in another embodiment, An apparatus for fabricating a strip of a separable fastening component, as described above. The apparatus comprises a plurality of mold plates, designated a fastener forming zone, having similar arcuate edges. The fastener forming zone further comprises fastening element mold cavities intersecting these edges and one face of the mold plate, the mold cavities being arranged into a plurality of segment forming regions. Circumscribing each of the segment forming regions, is a gasket mold cavity; and between each adjacent pair of segment forming regions, is a hinge forming region. The mold plates are arranged to form a cylindrical mold wheel having a circular surface formed by the arcuate edges of the mold plates such that the segment forming regions are spaced apart circumferentially around the cylindrical surface. The apparatus further comprises an extruder having a die whose surface is disposed close to the cylindrical surface for delivering moldable polymeric material to the mold cavities to form upstanding members and also to the surface to form therewith a polymeric base member strip to which the upstanding members formed in the mold cavities are integrally attached.
Each of the plates may comprise a circular plate. Alternatively, each of the plates may comprise less than an entire circular plate, the apparatus further comprising, for each fastener forming zone, a group of the plurality of plates, the members of the group being arranged with the arcuate edges forming the circular cylindrical surface of the mold wheel. The apparatus may further comprise additional pluralities of fastening plates, each of the additional pluralities comprising another fastener forming zone, the additional pluralities being arranged axially along the circular cylinder mold wheel to form side-by side fastener forming zones.
Still another embodiment of the invention is also an apparatus for fabricating a strip of a separable fastening component, as described above, comprising a plurality of mold plates, designated a fastener forming zone, having similarly curved edges. The mold plates comprise fastening element mold cavities intersecting these edges and one face of the mold plate, the mold cavities being arranged into a plurality of segment forming regions. Circumscribing each of the segment forming regions, a gasket mold cavity; and between each adjacent pair of segment forming regions, is a hinge forming region. The mold plates are arranged to form one component of a multi-piece injection molding assembly having a surface formed by the edges of the mold plates, such that the segment forming regions are spaced apart along the surface. A second component of the injection molding assembly is matable with the surface of the first component. Disposed within at least one of the components of the assembly, are passages for delivering moldable polymeric material to the mold cavities to form upstanding members and also to form therewith a polymeric base member strip to which the upstanding members formed in the mold cavities are integrally attached.